still frame camera solve
There is an addon called BLAM: Camera Calibration Toolkit it can be used to match geometry to still images.

It uses the grease pencil to determine the perspective and focal length, and has tools for geometry reconstruction.

see http://stuffmatic.com/blam-blender-camera-calibration-toolkit/
It can be downloaded here: http://stuffmatic.github.io/

UPDATE: Blam is no longer mantained and has been replaced by fspy:

https://fspy.io/

For a detailed post on how to use blam and Fspy read: How can I recreate geometry using a photograph?